Unable to understand RPC_E_SERVERFAULT Error

Question

I have a PowerShell Script that cycles through multiple Excel Workbooks, runs a few VBA routines, and then closes.

Unfortunately, I get the following error :

Exception calling "Run" with "1" argument(s): "The server threw an exception. (Exception from HRESULT: 0x80010105 (RPC_E_SERVERFAULT))"

THe strange thing is if I run the VBA Routines manually, I DO NOT get the above error. There is a lot of content online about this but nothing that solves my problem. ONe of the biggest culprits of this error is Foxit Addin, but I don't have that.

Any suggestions? Below is my ps1 script :

Function Excel-Quit {
    $Excel.Quit()
    # release the WorkSheet Com object
    [System.Runtime.Interopservices.Marshal]::ReleaseComObject($Workbook) | Out-Null
    # release the Excel.Application Com object
    [System.Runtime.Interopservices.Marshal]::ReleaseComObject($Excel) | Out-Null 
    # Force garbage collection
    [System.GC]::Collect()
    # Suspend the current thread until the thread that is processing the queue of finalizers has emptied that queue.
    [System.GC]::WaitForPendingFinalizers()
}


$Excel = New-Object -comobject Excel.Application
$Excel.Visible = $False
$Excel.DisplayAlerts = $False
$Excel.AskToUpdateLinks = $False
$ErrorActionPreference = "Stop"


$DTFormat = "yyyyMMddhhmm"
$TimeNow = Get-Date -Format "$DTFormat"

$Master_Bin = "C:\Users\administrator.hi\GCP\CGP - Reporting\Weekly_Hours_Reports"

$OutFile = "$env:LOGFILE" 

$Legacy = "$Env:INTRAPATH\_Legacy_Template_List.txt"
If (Test-Path "$Legacy") { Remove-Item "$Legacy"}
#New-Item "$Legacy"

$Invalid = 0
$LegacyTemplates = 0

$Array_Exclusion = @("_Master_Hours_Template_T&E.xlsm","Master_Hours_Template.xlsm")

$ExcelFiles = Get-ChildItem -Path "$Master_Bin\*" -Exclude *.zip,*.txt,*.csv -Include *.xlsm | `
                Where { !$_.PSisContainer }

Foreach($EFile in $ExcelFiles)
{
    
    Try { 
    
        # Ensure file is not already open
        [IO.File]::OpenWrite($EFile.fullname).close()
        
        # Get Excel file name without extension
        $FNWE = [io.path]::GetFileNameWithoutExtension("$($EFile.Name)")
        
        # Retrieve Date
        Try{
            $LWT = Import-CliXml "$Env:FILEPATH\CliXml\$FNWE.xml"
        }
        Catch{}

        #Process file only if $LWT does not equal LastWriteTime, indicating the file has been updated after formal refresh cadence (i.e. adding Notes, Adjustments etc)
        If($TimeNow -ne $EFile.LastWriteTime.ToString("$DTFormat")) {
            
            Try {

                $ReleaseObjectFLag = "True"
                Write-Output "Begin Processing : $($EFile.Name)"| Out-File -FilePath "$Outfile" -Append -Encoding ASCII
                
                $Workbook = $Excel.Workbooks.open("$Master_Bin\$($EFile.Name)", 0, $False)
                $Excel.Calculation = -4135
                $ExcelID = ((get-process excel | select MainWindowTitle, ID, StartTime | Sort StartTime)[-1]).Id

                Write-Output "                   Execute 'ProcessReport' Sub Routine"| Out-File -FilePath "$Outfile" -Append -Encoding ASCII
                
                # Refreshes ERP Report into Master Template 'Results' Tab
                $Excel.Run("ProcessReport")
                
                If("$($EFile.Name)" -ne "Master_Hours_Template.xlsm" -And "$($EFile.Name)" -ne "_Master_Hours_Template_T&E.xlsm"){
                    
                    Write-Output "                   Execute 'CalculateWorkbook' Sub Routine"| Out-File -FilePath "$Outfile" -Append -Encoding ASCII
                    $Excel.Run("CalculateWorkbook")     
                    
                    $Workbook.Sheets.Item('Cover Page').Activate()
                    # Check to ensure valid Client Name
                    $Value1 = $Workbook.Worksheets.Item('Cover Page').Cells.Item(5, 2)
                    
                    If($Value1.Text -ne 'Effective Start Date')
                    {
                        Write-Output "Old Template : $($EFile.Name)"| Out-File -FilePath "$Legacy" -Append -Encoding ASCII
                        $LegacyTemplates++
                    }
                    
                    Write-Output "                   Execute 'ClientPrep' Sub Routine"| Out-File -FilePath "$Outfile" -Append -Encoding ASCII
                    $Excel.Run("ClientPrep")
                    Write-Output " "| Out-File -FilePath "$Outfile" -Append -Encoding ASCII
    
                    $TimeNow = Get-Date -Format "$DTFormat" 
                    "$TimeNow" | Export-CliXml "$Env:FILEPATH\CliXml\$FNWE.xml" -Force
                }
                
                $Workbook.save()
                $Workbook.close()
                
            }
            Catch {
                $ErrorMessage = $_.Exception.Message
                Write-Output "Failed : Refresh $($EFile.Name)"| Out-File -FilePath "$Outfile" -Append -Encoding ASCII
                Write-Output "         $ErrorMessage"| Out-File -FilePath "$Outfile" -Append -Encoding ASCII
                $Workbook.save()
                $Workbook.close()
                
                Excel-Quit
                Exit 1
            }
        }
    }
    Catch {
        Write-Output "$_.Exception.Message"| Out-File -FilePath "$Outfile" -Append -Encoding ASCII
        Write-Output " "| Out-File -FilePath "$Outfile" -Append -Encoding ASCII
    }
    
    "$Invalid" | Export-CliXml "$Env:FILEPATH\CliXml\Invalid.xml"   -Force
    "$LegacyTemplates" | Export-CliXml "$Env:FILEPATH\CliXml\LegacyTemplates.xml"   -Force
}

# Call Excel-Quit Funtion
If($ReleaseObjectFLag) {Excel-Quit}

Exit 0

Thank you!